1. Field of the Invention
The present invention concerns a pyrimidine compound that can be utilized as ferroelectric liquid crystals.
2. Description of the Prior Art
Among liquid crystal compounds inducing twisted arrangements, i.e., ferroelectric liquid crystal compounds, there have been not a many compounds having the chiral smectic C phase at a temperature lower than the room temperature (hereinafter simply referred to as the Sc* phase).
Among them, pyrimidine liquid crystal compounds, for example, the compound 1 represented by the following formula (1) disclosed in Japanese Patent Laid Open No. Sho 61-22072 shows a relatively low Sc* phase-forming temperature. ##STR2##
However, the spontaneous polarization (Ps) of the compound is as small as less than 1 nC (cm.sup.2) at the greatest and, accordingly, it has a problem that the response under the room temperature is as slow as more than 1 ms.
In order to improve such a problem, the compound as shown by the formula (2) has been considered (refer to the pre-text for the 11th Liquid Crystals Meeting, 164 (S 60)). ##STR3##
The compound 2 shows a great spontaneous polarization value of greater than 10 nC/cm.sup.2. However, the compound 2 also has a problem that the Sc* phase does not appear at a low temperature lower than the room temperature.
The present invention has been made in view of the foregoing situation and it is an object thereof to provide a novel liquid crystal compound the Sc* phase of which is present near or less than the room temperature and having a large spontaneous polarization.
The pyrimidine compound according to the present invention is represented by the following general formula (1). ##STR4## where m, n represent respectively integers as: 4.ltoreq.m.ltoreq.8, 6.ltoreq.n.ltoreq.14.
The compound represented by the general formula (1) has the Sc* phase at a low temperature below the room temperature and also has a large spontaneous polarization.